1 /* $OpenBSD$ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-4-Clause
5 *
6 * Copyright (c) 2002 Jason L. Wright ([email protected])
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by Jason L. Wright
20 * 4. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
25 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
27 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
32 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
34 */
35
36 #include <sys/cdefs.h>
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/bus.h>
40 #include <sys/callout.h>
41 #include <sys/kernel.h>
42 #include <sys/malloc.h>
43 #include <sys/module.h>
44 #include <sys/random.h>
45 #include <sys/sysctl.h>
46 #include <machine/stdarg.h>
47
48 #include <dev/rndtest/rndtest.h>
49
50 static void rndtest_test(struct rndtest_state *);
51 static void rndtest_timeout(void *);
52
53 /* The tests themselves */
54 static int rndtest_monobit(struct rndtest_state *);
55 static int rndtest_runs(struct rndtest_state *);
56 static int rndtest_longruns(struct rndtest_state *);
57 static int rndtest_chi_4(struct rndtest_state *);
58
59 static int rndtest_runs_check(struct rndtest_state *, int, int *);
60 static void rndtest_runs_record(struct rndtest_state *, int, int *);
61
62 static const struct rndtest_testfunc {
63 int (*test)(struct rndtest_state *);
64 } rndtest_funcs[] = {
65 { rndtest_monobit },
66 { rndtest_runs },
67 { rndtest_chi_4 },
68 { rndtest_longruns },
69 };
70
71 #define RNDTEST_NTESTS nitems(rndtest_funcs)
72
73 static SYSCTL_NODE(_kern, OID_AUTO, rndtest, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
74 "RNG test parameters");
75 static int rndtest_retest = 120; /* interval in seconds */
76 SYSCTL_INT(_kern_rndtest, OID_AUTO, retest, CTLFLAG_RW, &rndtest_retest,
77 0, "retest interval (seconds)");
78 static struct rndtest_stats rndstats;
79 SYSCTL_STRUCT(_kern_rndtest, OID_AUTO, stats, CTLFLAG_RD, &rndstats,
80 rndtest_stats, "RNG test statistics");
81 static int rndtest_verbose = 1; /* report only failures */
82 SYSCTL_INT(_kern_rndtest, OID_AUTO, verbose, CTLFLAG_RW, &rndtest_verbose,
83 0, "display results on console");
84
85 struct rndtest_state *
rndtest_attach(device_t dev)86 rndtest_attach(device_t dev)
87 {
88 struct rndtest_state *rsp;
89
90 rsp = malloc(sizeof (*rsp), M_DEVBUF, M_NOWAIT);
91 if (rsp != NULL) {
92 rsp->rs_begin = rsp->rs_buf;
93 rsp->rs_end = rsp->rs_buf + sizeof(rsp->rs_buf);
94 rsp->rs_current = rsp->rs_begin;
95 rsp->rs_discard = 1;
96 rsp->rs_collect = 1;
97 rsp->rs_parent = dev;
98 callout_init(&rsp->rs_to, 1);
99 } else
100 device_printf(dev, "rndtest_init: no memory for state block\n");
101 return (rsp);
102 }
103
104 void
rndtest_detach(struct rndtest_state * rsp)105 rndtest_detach(struct rndtest_state *rsp)
106 {
107 callout_stop(&rsp->rs_to);
108 free(rsp, M_DEVBUF);
109 }
110
111 void
rndtest_harvest(struct rndtest_state * rsp,void * buf,u_int len)112 rndtest_harvest(struct rndtest_state *rsp, void *buf, u_int len)
113 {
114 size_t i;
115 /*
116 * If enabled, collect data and run tests when we have enough.
117 */
118 if (rsp->rs_collect) {
119 for (i = 0; i < len; i++) {
120 *rsp->rs_current = ((u_char *) buf)[i];
121 if (++rsp->rs_current == rsp->rs_end) {
122 rndtest_test(rsp);
123 rsp->rs_current = rsp->rs_begin;
124 /*
125 * If tests passed, turn off collection and
126 * schedule another test. Otherwise we keep
127 * testing until the data looks ok.
128 */
129 if (!rsp->rs_discard && rndtest_retest != 0) {
130 rsp->rs_collect = 0;
131 callout_reset(&rsp->rs_to,
132 hz * rndtest_retest,
133 rndtest_timeout, rsp);
134 break;
135 }
136 }
137 }
138 }
139 /*
140 * Only stir entropy that passes muster into the pool.
141 */
142 if (rsp->rs_discard)
143 rndstats.rst_discard += len;
144 else
145 /* MarkM: FIX!! Check that this does not swamp the harvester! */
146 random_harvest_queue(buf, len, RANDOM_PURE_RNDTEST);
147 }
148
149 static void
rndtest_test(struct rndtest_state * rsp)150 rndtest_test(struct rndtest_state *rsp)
151 {
152 int i, rv = 0;
153
154 rndstats.rst_tests++;
155 for (i = 0; i < RNDTEST_NTESTS; i++)
156 rv |= (*rndtest_funcs[i].test)(rsp);
157 rsp->rs_discard = (rv != 0);
158 }
159
160 static void
rndtest_report(struct rndtest_state * rsp,int failure,const char * fmt,...)161 rndtest_report(struct rndtest_state *rsp, int failure, const char *fmt, ...)
162 {
163 char buf[80];
164 va_list ap;
165
166 if (rndtest_verbose == 0)
167 return;
168 if (!failure && rndtest_verbose == 1) /* don't report successes */
169 return;
170 va_start(ap, fmt);
171 vsnprintf(buf, sizeof (buf), fmt, ap);
172 va_end(ap);
173 device_printf(rsp->rs_parent, "rndtest: %s\n", buf);
174 }
175
176 #define RNDTEST_MONOBIT_MINONES 9725
177 #define RNDTEST_MONOBIT_MAXONES 10275
178
179 static int
rndtest_monobit(struct rndtest_state * rsp)180 rndtest_monobit(struct rndtest_state *rsp)
181 {
182 int i, ones = 0, j;
183 u_int8_t r;
184
185 for (i = 0; i < RNDTEST_NBYTES; i++) {
186 r = rsp->rs_buf[i];
187 for (j = 0; j < 8; j++, r <<= 1)
188 if (r & 0x80)
189 ones++;
190 }
191 if (ones > RNDTEST_MONOBIT_MINONES &&
192 ones < RNDTEST_MONOBIT_MAXONES) {
193 if (rndtest_verbose > 1)
194 rndtest_report(rsp, 0, "monobit pass (%d < %d < %d)",
195 RNDTEST_MONOBIT_MINONES, ones,
196 RNDTEST_MONOBIT_MAXONES);
197 return (0);
198 } else {
199 if (rndtest_verbose)
200 rndtest_report(rsp, 1,
201 "monobit failed (%d ones)", ones);
202 rndstats.rst_monobit++;
203 return (-1);
204 }
205 }
206
207 #define RNDTEST_RUNS_NINTERVAL 6
208
209 static const struct rndtest_runs_tabs {
210 u_int16_t min, max;
211 } rndtest_runs_tab[] = {
212 { 2343, 2657 },
213 { 1135, 1365 },
214 { 542, 708 },
215 { 251, 373 },
216 { 111, 201 },
217 { 111, 201 },
218 };
219
220 static int
rndtest_runs(struct rndtest_state * rsp)221 rndtest_runs(struct rndtest_state *rsp)
222 {
223 int i, j, ones, zeros, rv = 0;
224 int onei[RNDTEST_RUNS_NINTERVAL], zeroi[RNDTEST_RUNS_NINTERVAL];
225 u_int8_t c;
226
227 bzero(onei, sizeof(onei));
228 bzero(zeroi, sizeof(zeroi));
229 ones = zeros = 0;
230 for (i = 0; i < RNDTEST_NBYTES; i++) {
231 c = rsp->rs_buf[i];
232 for (j = 0; j < 8; j++, c <<= 1) {
233 if (c & 0x80) {
234 ones++;
235 rndtest_runs_record(rsp, zeros, zeroi);
236 zeros = 0;
237 } else {
238 zeros++;
239 rndtest_runs_record(rsp, ones, onei);
240 ones = 0;
241 }
242 }
243 }
244 rndtest_runs_record(rsp, ones, onei);
245 rndtest_runs_record(rsp, zeros, zeroi);
246
247 rv |= rndtest_runs_check(rsp, 0, zeroi);
248 rv |= rndtest_runs_check(rsp, 1, onei);
249
250 if (rv)
251 rndstats.rst_runs++;
252
253 return (rv);
254 }
255
256 static void
rndtest_runs_record(struct rndtest_state * rsp,int len,int * intrv)257 rndtest_runs_record(struct rndtest_state *rsp, int len, int *intrv)
258 {
259 if (len == 0)
260 return;
261 if (len > RNDTEST_RUNS_NINTERVAL)
262 len = RNDTEST_RUNS_NINTERVAL;
263 len -= 1;
264 intrv[len]++;
265 }
266
267 static int
rndtest_runs_check(struct rndtest_state * rsp,int val,int * src)268 rndtest_runs_check(struct rndtest_state *rsp, int val, int *src)
269 {
270 int i, rv = 0;
271
272 for (i = 0; i < RNDTEST_RUNS_NINTERVAL; i++) {
273 if (src[i] < rndtest_runs_tab[i].min ||
274 src[i] > rndtest_runs_tab[i].max) {
275 rndtest_report(rsp, 1,
276 "%s interval %d failed (%d, %d-%d)",
277 val ? "ones" : "zeros",
278 i + 1, src[i], rndtest_runs_tab[i].min,
279 rndtest_runs_tab[i].max);
280 rv = -1;
281 } else {
282 rndtest_report(rsp, 0,
283 "runs pass %s interval %d (%d < %d < %d)",
284 val ? "ones" : "zeros",
285 i + 1, rndtest_runs_tab[i].min, src[i],
286 rndtest_runs_tab[i].max);
287 }
288 }
289 return (rv);
290 }
291
292 static int
rndtest_longruns(struct rndtest_state * rsp)293 rndtest_longruns(struct rndtest_state *rsp)
294 {
295 int i, j, ones = 0, zeros = 0, maxones = 0, maxzeros = 0;
296 u_int8_t c;
297
298 for (i = 0; i < RNDTEST_NBYTES; i++) {
299 c = rsp->rs_buf[i];
300 for (j = 0; j < 8; j++, c <<= 1) {
301 if (c & 0x80) {
302 zeros = 0;
303 ones++;
304 if (ones > maxones)
305 maxones = ones;
306 } else {
307 ones = 0;
308 zeros++;
309 if (zeros > maxzeros)
310 maxzeros = zeros;
311 }
312 }
313 }
314
315 if (maxones < 26 && maxzeros < 26) {
316 rndtest_report(rsp, 0, "longruns pass (%d ones, %d zeros)",
317 maxones, maxzeros);
318 return (0);
319 } else {
320 rndtest_report(rsp, 1, "longruns fail (%d ones, %d zeros)",
321 maxones, maxzeros);
322 rndstats.rst_longruns++;
323 return (-1);
324 }
325 }
326
327 /*
328 * chi^2 test over 4 bits: (this is called the poker test in FIPS 140-2,
329 * but it is really the chi^2 test over 4 bits (the poker test as described
330 * by Knuth vol 2 is something different, and I take him as authoritative
331 * on nomenclature over NIST).
332 */
333 #define RNDTEST_CHI4_K 16
334 #define RNDTEST_CHI4_K_MASK (RNDTEST_CHI4_K - 1)
335
336 /*
337 * The unnormalized values are used so that we don't have to worry about
338 * fractional precision. The "real" value is found by:
339 * (V - 1562500) * (16 / 5000) = Vn (where V is the unnormalized value)
340 */
341 #define RNDTEST_CHI4_VMIN 1563181 /* 2.1792 */
342 #define RNDTEST_CHI4_VMAX 1576929 /* 46.1728 */
343
344 static int
rndtest_chi_4(struct rndtest_state * rsp)345 rndtest_chi_4(struct rndtest_state *rsp)
346 {
347 unsigned int freq[RNDTEST_CHI4_K], i, sum;
348
349 for (i = 0; i < RNDTEST_CHI4_K; i++)
350 freq[i] = 0;
351
352 /* Get number of occurrences of each 4 bit pattern */
353 for (i = 0; i < RNDTEST_NBYTES; i++) {
354 freq[(rsp->rs_buf[i] >> 4) & RNDTEST_CHI4_K_MASK]++;
355 freq[(rsp->rs_buf[i] >> 0) & RNDTEST_CHI4_K_MASK]++;
356 }
357
358 for (i = 0, sum = 0; i < RNDTEST_CHI4_K; i++)
359 sum += freq[i] * freq[i];
360
361 if (sum >= 1563181 && sum <= 1576929) {
362 rndtest_report(rsp, 0, "chi^2(4): pass (sum %u)", sum);
363 return (0);
364 } else {
365 rndtest_report(rsp, 1, "chi^2(4): failed (sum %u)", sum);
366 rndstats.rst_chi++;
367 return (-1);
368 }
369 }
370
371 static void
rndtest_timeout(void * xrsp)372 rndtest_timeout(void *xrsp)
373 {
374 struct rndtest_state *rsp = xrsp;
375
376 rsp->rs_collect = 1;
377 }
378
379 static int
rndtest_modevent(module_t mod,int type,void * unused)380 rndtest_modevent(module_t mod, int type, void *unused)
381 {
382 switch (type) {
383 case MOD_LOAD:
384 return 0;
385 case MOD_UNLOAD:
386 return 0;
387 }
388 return EINVAL;
389 }
390
391 static moduledata_t rndtest_mod = {
392 "rndtest",
393 rndtest_modevent,
394 0
395 };
396 DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
397 MODULE_VERSION(rndtest, 1);
398